1. Field of the Invention
The present invention relates to a mechanical timepiece having a position-detecting device structured to detect a position of the mechanical timepiece and control rotation of the balance with hairspring based on a result of the position detection.
2. Background Information
(Conventional Mechanical Timepiece Structure)
In the conventional mechanical timepiece, as shown in FIG. 28 and FIG. 29, the mechanical-timepiece movement 1100 (mechanical body) has a main plate 1102 constituting a base plate for the movement. A hand setting stem 1110 is rotatably assembled in a hand-setting-stem guide hole 1102a of the main plate 1102. A dial 1104 (shown by the virtual line in FIG. 29) is attached to the movement 1100.
Generally, of the both sides of a main plate, the side having a dial is referred to as a xe2x80x9cback sidexe2x80x9d of the movement and the opposite side to the side having the dial as a xe2x80x9cfront sidexe2x80x9d. The train wheel assembled on the xe2x80x9cfront sidexe2x80x9d of the movement is referred to as a xe2x80x9cfront train wheelxe2x80x9d and the train wheel assembled on the xe2x80x9cback sidexe2x80x9d of the movement is as a xe2x80x9cback train wheelxe2x80x9d.
Furthermore, the state of directing up a side having the dial is referred to as a xe2x80x9cback horizontal statexe2x80x9d and the state of directing down the side having the dial is referred to as a xe2x80x9chorizontal-statexe2x80x9d.
Furthermore, the state of placing the dial vertical is referred to as a xe2x80x9cstanding positionxe2x80x9d, the state of placing the dial 12:00 division vertically above is referred to as a xe2x80x9c12:00 up (12U) positionxe2x80x9d, the state of placing the dial 3:00 division vertically above is referred to as a xe2x80x9c13:00 up (3U) positionxe2x80x9d, the state of placing the dial 6:00 division vertically above is referred to as a xe2x80x9c6:00 up (6U) positionxe2x80x9d, and the state of placing the dial 9:00 division vertically above is referred to as a xe2x80x9c9:00 up (9U) positionxe2x80x9d.
The hand setting stem 1110 is determined in axial position by a switch device including a setting lever 1190, a yoke 1192, a yoke spring 1194 and a back holder 1196. A winding pinion 1112 is rotatably provided on a guide axis portion of the hand setting stem 1110. When rotating the hand setting stem 1110 in a state the hand setting stem 1110 is in a first hand-setting-stem position closest to an inward of the movement along a rotation axis direction (0 stage), the winding pinion 1112 rotates through rotation of the clutch wheel. A crown wheel 1114 rotates due to rotation of the winding pinion 1112. A ratchet wheel 1116 rotates due to rotation of the crown wheel 1114. By rotating the ratchet wheel 1116, a mainspring 1122 accommodated in a barrel complete 1120 is wound up. A center wheel and pinion 1124 rotates due to rotation of the barrel complete 1120. An escape wheel and pinion 1130 rotates through rotation of a fourth wheel and pinion 1128, third wheel and pinion 1126 and center wheel and pinion 1124. The barrel complete 1120, center wheel and pinion 1124, third wheel and pinion 1126 and fourth wheel and pinion 1128 constitutes a front train wheel.
An escapement/speed-control device for controlling rotation of the front train wheel includes a balance with hairspring 1140, an escape wheel and pinion 1130 and pallet fork 1142. The balance with hairspring 1140 includes a balance stem 1140a, a balance wheel 1140b and a stud mainspring 1140c. Based on the center wheel and pinion 1124, an hour pinion 1150 rotates simultaneously. A minute hand 1152 attached on the hour wheel 1150 indicates xe2x80x9cminutexe2x80x9d. The hour pinion 1150 is provided with a slip mechanism for the center wheel and pinion 1124. Based on rotation of the hour pinion 1150, an hour wheel 1154 rotates through rotation of a minute wheel. An hour hand 1156 attached on the hour wheel 1154 indicates xe2x80x9chourxe2x80x9d.
The barrel complete 1120 is rotatably supported relative to the main plate 1102 and barrel bridge 1160. The center wheel and pinion 1124, the third wheel and pinion 1126, the fourth wheel and pinion 1128 and the escape wheel and pinion 1130 are rotatably supported relative to the main plate 1102 and train wheel bridge 1162. The pallet fork 1142 is rotatably supported relative to the main plate 1102 and pallet fork bridge 1164. The balance with hairspring 1140 is rotatably supported relative to the main plate 1102 and balance bridge 1166.
The stud mainspring 1140c is a thin leaf spring in a spiral (helical) form having a plurality of turns. The stud mainspring 1140c at an inner end is fixed to a stud ball 1140d fixed on the balance stem 1140a, and the stud mainspring 1140c at an outer end is fixed by screwing through a stud support 1170a attached to a stud bridge 1170 fixed on the balance bridge 1166.
A regulator 1168 is rotatably attached on the balance bridge 1166. A stud bridge 1168a and a stud rod 1168b are attached on the regulator 1168. The stud mainspring 1140c has a near-outer-end portion positioned between the stud bridge 1168a and the stud rod 1168b. 
(Conventional Mechanical Timepiece Mainspring Torque and Balance with Hairspring Swing Angle)
Generally, in the conventional representative mechanical timepiece, as shown in FIG. 30, the torque on the mainspring decreases while being rewound as the sustaining time elapses from a state the mainspring is fully wound (full winding state). For example, in the case of FIG. 30, the mainspring torque in the full winding state is about 27 gxc2x7cm, which become about 23 gxc2x7cm at a lapse of 20 hours from the full winding state and about 18 gxc2x7cm at a lapse of 40 hours from the full winding state.
Generally, in the conventional representative mechanical timepiece, as shown in FIG. 31, the decrease of mainspring torque also decreases a swing angle of the balance with hairspring. For example, in the case of FIG. 31, the swing angle of the balance with hairspring is approximately 240 to 270 degrees when the mainspring torque is 25 to 28 gxc2x7cm while the swing angle of the balance with hairspring is approximately 180 to 240 degrees when the mainspring torque is 20 to 25 gxc2x7cm.
(Conventional Mechanical Timepiece Instantaneous Watch Error)
Referring to FIG. 32, there is shown transition of an instantaneous watch error (numeral value indicative of timepiece accuracy) against a swing angle of a balance with hairspring in the conventional representative mechanical timepiece. Here, xe2x80x9cinstantaneous watch errorxe2x80x9d refers to xe2x80x9ca value representative of fast or slow of a mechanical timepiece at a lapse of one day on the assumption that the mechanical timepiece is allowed to stand while maintaining a state or environment of a swing angle of a balance with hairspring upon measuring a watch errorxe2x80x9d. In the case of FIG. 32, the instantaneous watch error delays when the swing angle of the balance with hairspring is 240 degrees or greater or 200 degrees or smaller.
For example, in the conventional representative mechanical timepiece, as shown in FIG. 32, the instantaneous watch error is about 0 to 5 seconds per day (about 0 to 5 second fast per day) when the swing angle of the balance with hairspring is about 200 to 240 degrees while the instantaneous watch error becomes about xe2x88x9220 seconds per day (about 20 seconds slow per day) when the swing angle of the balance with hairspring is about 170 degrees.
Referring to FIG. 27, there is shown a transition of an instantaneous watch error and a lapse time upon rewinding the mainspring from a full winding state in the conventional representative mechanical timepiece. Here, in the conventional mechanical timepiece, the xe2x80x9cwatch errorxe2x80x9d indicative of timepiece advancement per day or timepiece delay per day is shown by a bold thin line in FIG. 27, which is obtainable by integrating over 24 hours an instantaneous watch error against a lapse time of rewinding the mainspring from the full winding.
Generally, in the conventional mechanical timepiece, the instantaneous watch error slows down because the mainspring torque decreases and the balance-with-hairspring swing angle decreases as the sustaining time elapses with the mainspring being rewound from a full winding state. Due to this, in the conventional mechanical timepiece, the instantaneous watch error in a mainspring full winding state is previously put forward in expectation of timepiece delay after lapse of a sustaining time of 24 hours, thereby previously adjusting plus the xe2x80x9cwatch errorxe2x80x9d representative of timepiece advancement or delay per day.
For example, in the conventional representative mechanical timepiece, as shown by a bold line in FIG. 27, the instantaneous watch error in a full winding state is about 5 seconds per day (about 5 seconds fast per day). However, when 20 hour elapses from the full winding state, the instantaneous watch error becomes about xe2x88x921 seconds per day (about 1 second slow per day). When 24 hours elapses from the full winding state, the instantaneous watch error becomes about xe2x88x925 second per day (about 5 seconds slow per day). When 30 hours elapses from the full winding state, the instantaneous watch error becomes about 15 seconds per day (about 15 seconds slow per day).
(Conventional Mechanical Timepiece Position and Instantaneous Watch Error)
Meanwhile, in the conventional representative mechanical timepiece, the instantaneous watch error in a xe2x80x9chorizontal positionxe2x80x9d and a xe2x80x9cback horizontal positionxe2x80x9d is on a faster side than the instantaneous watch error in a xe2x80x9cstanding positionxe2x80x9d.
For example, the conventional representative mechanical timepiece, when in a xe2x80x9chorizontal positionxe2x80x9d and a xe2x80x9cback horizontal position, in a full winding state has an instantaneous watch error of about 8 seconds per day (about 8 seconds fast per day), as shown by a bold line in FIG. 33. When 20 hours elapses from the full winding state, the instantaneous watch error becomes about 3 seconds per day (about 3 seconds fast per day). When 24 hours elapses from the full winding state, the instantaneous watch error becomes about xe2x88x922 seconds per day (about 2 seconds slow per day). When 30 hours elapses from the full winding state, the instantaneous watch error becomes about xe2x88x9212 seconds per day (about 12 seconds slow per day).
Contrary to this, the conventional representative mechanical timepiece, when in a xe2x80x9cstanding positionxe2x80x9d, in a full winding state has an instantaneous watch error of about 3 seconds per day (about 3 seconds fast per day), as shown by a thin line in FIG. 33. When 20 hours elapses from the full winding state, the instantaneous watch error becomes about xe2x88x922 seconds per day (about 2 seconds slow per day). When 24 hours elapses from the full winding state, the instantaneous watch error becomes about xe2x88x927 seconds per day (about 7 seconds slow per day). When 30 hours elapses from the full winding state, the instantaneous watch error becomes about xe2x88x9217 seconds per day (about 17 seconds slow per day).
(Representative Documents Disclosing Related Arts)
The conventional balance-with-hairspring swing angle adjusting device disclosed in Japanese Utility Model Laid-open No. 41675/1979 has a swing angle adjusting plate to cause eddy current each time the balance magnet swingingly approaches thereby applying a brake force to the balance with hairspring.
Meanwhile, the conventional position-detecting device disclosed in Japanese Patent Laid-open No. 307805/1994 has a hollow outer spherical member and an inner spherical member fixed by providing a predetermined layer space in an outer spherical member hollow portion, so that a fluid conductor is arranged between a first conductive region including an electrode provided on an inside entire region of the outer spherical member and a second conductive region including a plurality of electrodes provided spotted on an outer side of the inner spherical member. In the conventional position-detecting device, the fluid conductor can move in the layer space between the first conductive region and the second conductive region. A position of the device can be structurally detected by conduction of the fluid conductor between the one of electrode in the second conductive region and the electrode in the first conductive region.
(Object of the Invention)
It is an object of the invention to provide a mechanical timepiece capable of detecting a position of the mechanical timepiece and, by a result of the detection, control a swing angle of the balance with hairspring within a constant range.
Furthermore, another object of the invention is to provide a mechanical timepiece which is less in instantaneous watch rate change and accurate even after lapse of time from a full winding state.
The present invention is, in a mechanical timepiece structured having a mainspring constituting a power source for the mechanical timepiece, a front train wheel rotating due to rotational force given upon rewinding the mainspring and an escapement/speed-control device for controlling rotation of the front train wheel, the escapement/speed-control device being structured including a balance with hairspring alternately repeating right and left rotation, an escape wheel and pinion rotating based on rotation of the front train wheel and a pallet fork controlling rotation of the escape wheel and pinion based on operation of the balance with hairspring, the mechanical timepiece characterized by comprising: a switch mechanism structured to output an on signal when a rotation angle of the balance with hairspring becomes a predetermined threshold or greater, and an off signal when the rotation angle of the balance with hairspring is not excess of the predetermined threshold; a balance-with-hairspring rotation angle control mechanism structured to apply such a force as suppressing against rotation of the balance with hairspring when the switch mechanism outputs an on signal; and a position-detecting device for detecting a position of the mechanical timepiece.
The mechanical timepiece of the invention is structurally characterized in that the balance-with-hairspring rotation angle control mechanism is controlled in operation based on a result of detection of a position of the mechanical timepiece detected by the position-detecting device.
In the mechanical timepiece of the invention, the switch mechanism is preferably structured to output an on signal when a stud mainspring provided on the balance with hairspring contacts a contact member constituting a switch lever.
Also, in the mechanical timepiece of the invention, the balance-with-hairspring rotation angle control mechanism preferably includes a balance magnet provided on the balance with hairspring and coils arranged to exert a magnetic force to the balance magnet, and the coils being structured to apply a magnetic force to the balance magnet to suppress rotation of the balance with hairspring when the switch mechanism outputs an on signal, and not to apply a magnetic force to the balance magnet when the switch mechanism outputs an off signal.
Also, in the mechanical timepiece of the invention, the position-detecting device preferably includes a case having a hexahedron shape, electrodes respectively arranged on a one-to-one basis to inner surfaces of the case, and a conductive fluid accommodated in the case.
Also, in the mechanical timepiece of the invention, the conductive fluid preferably structurally takes a state of contacting five of the electrodes, a state of contacting four of the electrodes, and a state of contacting three.
Also, in the mechanical timepiece of the invention, the position-detecting device preferably includes a case having a hexahedron shape, electrodes respectively arranged in plurality to inner surfaces of the case, and a conductive fluid accommodated in the case.
Also, in the mechanical timepiece of the invention, the position-detecting device preferably includes a case having a hexahedron shape and formed of an insulating material, six electrodes respectively arranged to inner surfaces of the case, and a conductive fluid accommodated in the case, and further having a plurality of resistances different in resistance value provided in a manner corresponding to a conducting state of the six electrodes, whereby one of the resistances is put into connection to the coils based on a result of detection of a position of the mechanical timepiece detected by the position-detecting device.
With the structure as above, it is possible to effectively control the rotation angle of the balance with hairspring of the mechanical timepiece thereby improving the accuracy of the mechanical timepiece.